For most of the day it was like discovering that the best-selling detective novel you had been given to read consisted of blank pages. Then, halfway through the final chapter, the words came to blazing life as the Tour de France once again rewarded the patience of its adherents old and new with an incident-packed finale in which Bradley Wiggins hung on to his yellow jersey, saw one of his principal rivals display an unexpected and possibly fatal weakness, crossed the line arm in arm with the other, and received a perhaps unwelcome reminder of the strength of his chief lieutenant.

The day was all set up to be one in which the race leader would be subjected to constant danger. At the end, however, the man who appeared to be in the position to pose the greatest threat to Wiggins's chances of becoming the first British rider to win the Tour de France was not Cadel Evans or Vincenzo Nibali but Chris Froome, his own compatriot and team-mate.

When Froome staged a sudden attack on the yellow jersey group inside the final 5km, having previously taken over the task of shepherding Wiggins up the last long climb from Michael Rogers and Richie Porte, it seemed a strange decision – unless his team leader went with him, with the aim of gaining more time on his principal opponents in the general classification.

But Wiggins failed to accelerate, and within a couple of hundred metres Froome could be seen listening to words coming through his earpiece before ending his solo effort and dropping back to rejoin the yellow jersey. With less than a kilometre to go, when there was no longer a threat of Wiggins losing a significant amount of time, Froome sprinted again, and this time was not restrained by a message in his ear.

On a blindingly sunny day, shady thoughts leapt to the fore. Had Froome, inadvertently or otherwise, exposed Wiggins' principal weakness when required to accelerate suddenly during a long climb? Dave Brailsford, Sky's team principal, had no explanation for the double move. In the pre-race briefing that morning Froome had been told that he could attack in the last 500m to improve his position in the overall standings. Nothing had been mentioned about an earlier attack. "It certainly wasn't my instruction," Brailsford said. "But you can never have enough time on GC." Froome, he pointed out, had lost almost a minute and a half early in the race and had been working wholeheartedly for Wiggins ever since.

Asked if Froome could be in a position to win the race were he riding for another team, Brailsford replied: "That's a highly hypothetical question. We'll never be able to answer it. But we've got first and second in the general classification, which is the perfect position to be in."

Wiggins' response was more puzzling. Asked about Froome's first attack, he said: "I was concentrating on my own effort. There was a lot of noise and a lot of things going on on the radio and a bit of confusion about what we were doing at that point." A couple of minutes later he was asked again. "I don't know who called him back," he said. "My [ear]piece had fallen out." He added that there had been a morning discussion about Froome making a late attack in order to make up time on Evans.

"I'll follow orders at all costs," the mild-mannered Froome said. "I'm part of a team and I have to do what the team asks me to do. Our plan is to look after Bradley."

Pressed on why he thought Wiggins's chance of victory was better than his own, he responded: "He's just as strong as me, I think, and stronger than me in the time trial."

When a Twitter squabble broke out between the team's various wives and girlfriends, it seemed that the Team Sky bus might be about to become the scene of the Tour's most intense internecine war since Bernard Hinault and Greg LeMond fought each other for victory while riding for La Vie Claire in 1986. Whatever diplomatic skills Brailsford needed to heal the rift between Wiggins and Mark Cavendish after their Madison disaster in the Beijing velodrome four years ago may be required again in the coming days.

A different kind of drama had been expected on Thursday, but it took a long time coming. From the start in Albertville, the site of the 1992 Winter Olympics, the riders were sent over two giant cols, the Madeleine and Croix de Fer, before finishing on the grind up to the ski station of La Toussuire. The parcours had seemed to offer the perfect opportunity for one of the climbers in the top 10 – most likely Evans, in second place at the start of the day, or Nibali, lying fourth.

For several hours, however, their unwillingness to take the initiative left spectators lamenting the absence of the injured Andy Schleck and the suspended Alberto Contador, who fought a classic hand-to-hand battle over the slopes of the Tourmalet on a murky afternoon two years ago. Those whose memories stretch back to such epic climbers as Charly Gaul, Federico Bahamontes and Marco Pantani were wondering whether to go into mourning for the entire sport.

An early break involving a couple of dozen riders was still forming and reforming four minutes ahead of the main peloton, led by Sky, when Evans mounted an attack on the second climb, the mighty Col du Glandon, which was being used as a sort of stepladder to the 2,067m summit of the Croix de Fer. "I was a bit surprised," Wiggins remarked. "There was still a hell of a long way to go and we were riding a strong tempo with Richie [Porte] and Mick [Rogers]. It's not something I'd have had the balls to do."

The attack lasted five kilometres, and saw Evans joined by two team-mates, Tejay van Garderen and Amaël Moinard. But, as has often been the case when Evans takes the initiative, it came to nothing, and the Australian resumed his place in the bunch.

Up at the front Pierre Rolland, left, the admirable young Europcar rider who acted as Thomas Voeckler's super-domestique last year while also finding time to win the stage to the Alpe d'Huez, was sorting out a group of four with whom to ride to the finish. Robert Kiserlovski, a Croatian rider with Astana, Vasil Kiryienka, a Belarussin with Movistar, and Chris Anker Sorensen, a Dane with Saxo Bank-Tinkoff, were the Frenchman's companions, until they fell away and he was able to ride in lonely splendour up the final slopes to the ski station at La Toussuire, where he had 55 seconds to enjoy his triumph before the next rider came home.

Local joy was unconfined when that turned out to be Thibaut Pinot, the 22-year-old who is the youngest rider in the race and who, wearing the jersey of FDJ-BigMat, another French team, won the mountain stage to Porrentuy on Sunday. Pinot had been prominent throughout the closing stages and outsprinted Froome to the line in a further demonstration that an era of almost unrelieved bleakness for France, which began when Hinault won his last Tour in 1985, may be coming to an end.

Evans, who had lurked in Wiggins' slipstream after the failure of his attack, cracked with 5km to go and was accompanied home by a solicitous Van Garderen, his fellow BMC rider, almost a minute behind Wiggins. "It wasn't Cadel's best day," the 23-year-old American said. "But if he can shake it off, we'll get some time back."

Nibali had failed to make an expected attack on the plunging descent from the third climb of the day, the Col du Mollard, where there was scarcely a straight metre of road for more than 5km and the aroma of freshly laid asphalt patches filled the rider's nostrils. He had two attempts in the last 10km, the first of them in the shadow of the handsome village church at Fontcouverte, but both were comfortably neutralised before Wiggins extended the hand of friendship on the finish line.

Nibali can be expected to try again on Friday on a 226km stage that begins at Saint Jean de Maurienne and takes in the first category climbs of the Grand Cucheron and the Granier before ending in the Ardeche, where a climb before the finish in Annonay-Davézieux may produce fireworks.